改进的ReliefF在ICP特征选择中的应用

妊娠期肝内胆汁淤积症(ICP)是妊娠期严重危害母婴的并发症,原始的ICP数据集中含有大量的生物标志物信息,特征间通常会存在相关性,且不同妊娠结局间的人数差异较大.论文针对ICP数据集的高冗余和非平衡性,提出了一种新的特征选择算法—SC-ReliefF.SC-ReliefF算法在ReliefF的基础上,根据类内平均距离提出了新的样本选择方法,能很好地适应非平衡数据的特点;同时为了减少特征冗余,SC-ReliefF算法引入余弦相似度,将其作为特征冗余度的度量方式,提出一种去冗余方法,能够得到更小的特征子集.在医院提供的临床数据实验表明,SC-ReliefF算法与ReliefF、mRMR和RS-ReliefF相比得到的ICP特征子集规模较小,且在SVM和BP-NN上具有较好的分类效果,能够提升学习的效率.     

基于固态成型工艺聚合物基复合材料自增强技术研究进展

针对当前聚合物实际强度远低于理论强度的问题,介绍了固态挤出、固态拉伸等自增强技术的制备流程及其工艺特点。此外,通过分析固态形变过程中试样内部的微观形貌与分子构型,进一步研究聚合物基复合材料固态加工过程中的自增强机理。最后,通过归纳总结影响试样增强效果的因素,进一步探索聚合物基复合材料的性能上限,拓宽其在不同领域的高性能化应用。     

榆树林油田扶余油层重复压裂裂缝转向研究

确定裂缝是否转向及其主要影响因素是目前榆树林油田重复压裂问题之一。通过Fracpro PT软件拟合分析了现场压裂数据,施工过程净压力7.8~17.0 MPa,目前最大最小主应力差为9.6~20.6 MPa,平均14.4MPa;采用重复压裂应力分析软件计算了油水井在不同生产压差和裂缝缝长与缝宽条件下生产时不同位置处的最大最小应力差的演变,5 mm缝宽比1.6 mm缝宽最大最小应力差小1.0 MPa;120 m缝长比60 m缝长最大与最小应力差小0.5 MPa;22 MPa比17 MPa的油水井生产压差的最大最小应力差小2.0 MPa。初始最大最小主应力差16MPa对该油田部分井重复压裂实现裂缝转向具有较大难度,不易形成新缝;目前最大最小应力差小、初次压裂形成宽和长的裂缝、压后油水井生产压差较大及重复压裂过程中净压力较高的井层有利于重复压裂时发生裂缝的重定向而产生新裂缝。     

基于Web的数控机床误差参数辨识系统

误差参数辨识是误差补偿的前提.本文首先介绍了误差辨识的原理,然后采用B/S模式、3层体系结构和.Net Remoting技术设计并实现了基于Web的误差参数辨识系统.通过实例运行,证明该系统的设计是可行的,从而为实现基于Web的误差补偿技术奠定基础.     

海上稠油水平井蒸汽驱汽窜封堵体系评价与研究

针对海上蒸汽驱水平井汽窜问题,提出了一种有效的封堵方法。通过实验研制了一种新型的低成本耐高温药剂体系,分别对体系的注入性、成胶时间、耐温性和封堵能力进行了评价。实验结果表明,该体系在室温下黏度约为3 mPa·s,注入性良好。在80℃时开始凝固,最终形成块状固态。该体系能承受350℃高温,残余阻力系数高达30,具有良好的堵剂性能。通过三维模型实验和数值模拟,建立了均匀封堵技术,该技术的优点是有效封堵汽窜、注入压力适宜、提高采收率效果明显,对海上稠油蒸汽驱的开发具有十分重要的意义。     

白炭黑改性剂对溶聚丁苯橡胶性能的影响

将偶联剂Si69和KH550、活性剂PEG4000和DPG用作白炭黑改性剂,研究其对白炭黑填充溶聚丁苯橡胶(SSBR)性能的影响。结果表明:改性剂种类和用量对硫化胶性能有较大影响,Si69,KH550,PEG4000和DPG的最佳用量分别为4,8,4和6份;在最佳改性剂用量下,与未改性白炭黑胶料相比,改性白炭黑胶料的加工安全性好,硫化速率快,物理性能、耐磨性能和抗湿滑性能提高;在4种改性剂中,Si69和KH550改性白炭黑在橡胶中的分散性较好,胶料具有较高的物理性能、耐磨性能、抗湿滑性能及较低的滚动阻力。     

Core–shell type multi‐arm azide polymers based on hyperbranched copolyether as potential energetic materials in solid propellants

A series of novel multi‐arm azide copolymers (POGs) with the same hyperbranched poly[3‐ethyl‐3‐(hydroxymethyl)oxetane] core (PEHO‐c) and different content of linear glycidyl azide polymer shell (GAP‐s) have been synthesized by sequential cationic ring‐opening polymerization and azidation. Detailed structural information of these copolyethers was deduced from Fourier transform infrared, ¹H NMR and inverse gated decoupled ¹³C NMR spectroscopies, matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry, gel permeation chromatography and elemental analysis. The molecular weight of POG having GAP‐s and PEHO‐c with a molar ratio 14.95:1 (R_s/c) was around 31 000 g mol^?1, far above that of linear GAP (around 4000 g mol^?1). The apparent viscosity and glass transition temperature (?51 to ?23 °C) decreased first and then slightly increased with increasing molecular weight. Thermal analysis revealed that all the obtained POGs exhibited excellent resistance to thermal decomposition up to 220 °C. Moreover, the energetic properties, investigated using oxygen bomb calorimetric measurements, indicated that the enthalpy of formation of the POGs was higher than that of general linear GAP, but similar to that of branched GAP under reasonable R_s/c. The compatibilities of the POGs with common materials used in solid propellants were studied using differential scanning calorimetry and the results indicated that the POGs had good compatibility with these materials. © 2017 Society of Chemical Industry     

Overlapping community detection based on discrete biogeography optimization

Community detection can be used to help mine the potential information in social networks, and uncovering community structures in social networks can be regarded as clustering optimization problems. In this paper, an overlapping community detection algorithm based on biogeography optimization is proposed. Firstly, the algorithm takes the method of label propagation based on local max degree and neighborhood overlap for initial network partitioning. The preliminary partition result used to construct initial population by cloning and mutating to accelerate the algorithm’s convergence. Next, to make biogeography optimization algorithm suitable for community detection, we design problem-specific migration rules and mutation operators based on a novel affinity degree to improve the effectiveness of the algorithm. Experiments on benchmark test data, including two synthetic networks and four real-world networks, show that the proposed algorithm can achieve results with better accuracy and stability than the compared evolutionary algorithms.     

多种地基处理桩型的结合应用

地基处理是污水厂结构设计的重要组成部分。本文主要介绍采用大功率、大直径振冲碎石桩结合锚桩的方法解决地基液化、沉降、承载力和池体抗浮等综合问题 ,达到了既充分利用土体固有的特性、又经济合理的处理目的 ,并对应用中引发的共同作用、底板计算等问题作了分析。